With the terms “great” and “legend” neatly tucked into the subtitle, it’s no surprise that Elizabeth Wilson’s biography of Mstislav Rostropovich is a worshipful portrait. Chalk it up to a student’s devotion to her former mentor, perhaps, although many readers will feel that the tone is a good fit for Rostropovich, one of the most celebrated musicians of the 20th century. “An overwhelming life force in the form of a cellist” is how one leading critic summed up Slava, as he was familiarly known, upon his death at 80 last April. Wilson studied with Rostropovich in the ’60s at the Moscow Conservatory, where Rostropovich taught until 1974, and there is eye-glazing detail on those core years, particularly on the period spent at the conservatory coaching the cellists of “Class 19.” The book quickly peters out after that date, though, following Rostropovich’s reluctant emigration to the West. The events of his later life — his famous impromptu performance before the Berlin Wall in 1989, his 17-year stint as music director of the National Symphony Orchestra, in Washington, D.C. — earn only a few sentences in the epilogue. Still, on Rostropovich’s Soviet years, Wilson delivers amply, culminating in the cellist’s defiant public support for the dissident author Aleksandr Solzhenitsyn, a stance that had disastrous consequences for Rostropovich. If Wilson treads lightly on broader themes (like Rostropovich’s commitment to artistic liberty), she finds her stride in well-sourced, lucid discussion of the cellist’s brilliance as a teacher, his fruitful interactions with composers, and the musical values he held dear — values that, thankfully, can still be heard on his many splendid recordings. -